[quote] Are there benefits to doing this sometimes? Speaking as a 5/10k runner. [quote]
there are, as far as I am aware, no studies comparing doing your weights straight after a workout versus doing the weights later, or the next day.
there is good evidence to suggest that, if you want to do them both on the same day, you, that is you the 5km/10km runner, should do the track workout first, then do the weights. athletes in explosive events, jumpers, throwers, sprinters etc., should do them the other way round, weights first, then track.
I personally do my weights/gym session right after a track workout. I cool down on the track as normal. then I go inside and eat a banana and a peanut butter sandwich I brought with me while changing into clean kit. then I jog a mile on the treadmill. then I do around fifteen minutes of foam rolling and then I start my gym session.
I also have a water bottle with me and re-fill it four or five times from the coolers in the gym. this definitely helps.
cheers.